William has walked his dog for a total of $45$ miles since he started walking daily. He has been walking $5$ miles each day. For how many days has William been walking?
Explanation: The number of days that William has been walking is the total number of miles walked divided by the number of miles walked each day. $45\text{ miles} \div 5\text{ miles per day} = \text{number of days walking}$ $45\text{ miles} \div 5\text{ miles per day} = 9\text{ days}$